红外焦平面技术的重要进展—单片式SiGe红外焦平面阵列的物理基础和关键技

由ＳｉＧｅ合金与Ｓｉ构成的应变层异质结构、量子阱是８０年代中期发展起来的一种新型半导体材料。本文着重讨论了单片式ＳｉＧｅ红外焦平面阵列的物理基础、高质量ＳｉＧｅ材料的制备以及低温ＳｉＧｅ器件研制中的几个关键技术。     

红外焦平面技术的重要进展──单片式SiGe红外焦平面阵列的物理基础和关键技术

由ＳｉＧｅ合金与Ｓｉ构成的应变层异质结构、量子阱是８０年代中期发展起来的一种新型半导体材料。本文着重讨论了单片式ＳｉＧｅ红外焦平面阵列的物理基础、高质量ＳｉＧｅ材料的制备以及低温ＳｉＧｅ器件研制中的几个关键技术。     

非晶态半导体／金属薄膜的分形晶化

本文综述非晶态半导体／金属薄膜退火过程中金属诱导非晶态半导体晶化的研究，综述对若干非晶态半导体与金属组成的薄膜（Ｇｅ－Ａｕ、Ｇｅ－Ａｇ、Ｇｅ－Ａｌ、Ｇｅ－Ｓｅ、Ｇｅ－ｐｄ、Ｓｉ－Ａｇ、Ｓｉ－Ａｌ、Ｓｉ－ｐｄ、Ｓｉ－Ｃｕ、ｓｉｃ－Ａｌ、Ｓｉ＿３Ｎ＿４－Ａ１）晶化后形成的图形进行的分形研究，内容包括分形形成的实验规律、根据微结构电镜观测结果提出的随机逐次成核模型、以及对分形晶化进行的计算机模拟。     

Si1—xGex／Si脊形波导X型分支器的研制

采用分子束外延方法制作低损耗Ｓｉ１－ｘＧｅ／Ｓｉ异质结脊形光波导，在Ｘ型交叉波导上实现了Ｓｉ１－ｘＧｅｘ／Ｓｉ光分支器的功能，设计中采用了ＳｉＧｅ大截面脊形波导的单模条件和交波导传输特性分析的结果。Ｘ型光分支器的实现为进下Ｓｉ１－ｘＧｅｘ／Ｓｉ光开关和光电调制器积累了经验。     

应变Si_（1－x）Ge_x层本征载流子浓度和有效态密度的温度特性分析

本文计算了应变Ｓｉ１－ｘＧｅｘ层的本征载流子浓度及导带和价带有效态密度．首次用解析的方法研究了它们与Ｇｅ组份ｘ和温度Ｔ的依赖关系．我们发现，随Ｇｅ组份ｘ的增加，由于Ｓｉ１－ｘＧｅｘ层中应力的影响，导带和价带有效态密度随之快速减少，而本征载流子浓度却随之而近乎指数式地增加．而且，温度Ｔ越低，导带和价带有效态密度随Ｇｅ组份ｘ的增加而减少得越快，而本征载流子浓度上升得越快．同时，我们还发现，具有大Ｇｅ组份ｘ的应变Ｓｉ１－ｘＧｅｘ层，其用Ｓｉ的相应参数归一化的导带和价带有效态密度及它们的积与温度Ｔ的依赖关系弱，而具有小Ｇｅ组份ｘ的应变Ｓｉ１－ｘＧｅｘ层，上述归一化参数与温度Ｔ的依赖关系强，这和目前仅有的文献［８］中它们于温度依赖关系的定性研究结果相一致．本文得到的定量结果对探索应变ＳｉＧｅ层的物理性质、对应变ＳｉＧｅ层基器件的设计、模拟及对低温ＳｉＧｅ器件物理的理解有重要意义．     

1.55μmSi_(1-x)Ge_x光波导与Si_(1-x)Ge_x/Si多量子阱探测器集成的优化设计

对１．５５μｍ波长的Ｓｉ１－ｘＧｅｘ光波导和Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱（ＭＱＷ）红外探测器的集成器件结构进行了系统的分析和优化设计。优化结果为：１）对Ｓｉ１－ｘＧｅｘ光波导，Ｇｅ含量ｘ＝０．０５，脊宽、高和腐蚀深度分别为８、３和２．６μｍ；２）对Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器，Ｇｅ含量ｘ＝０．５，探测器由厚度为５５０ｎｍ、２３个周期的６ｎｍＳｉ０．５Ｇｅ０．５＋１７ｎｍＳｉ组成，长度约２ｍｍ。结果表明，这种结构器件的内量子效率可达８８％。     

Si Ge量子阱和超晶格的光发射

系统地介绍了近几年来国内外对ＳｉＧｅ量子阱及短周期超晶格光发射的研究现状。由于Ｓｉ，Ｇｅ材料及器件在微电子学领域内的无可比拟的优越性，所以，超过９０％的芯片技术是Ｓｉ基的，然而，由于Ｓｉ，Ｇｅ是间接带隙，载流子跃迁几率小，其光电应用受到很大的限制，为此，人们作出了不懈的努力，并取得了可喜的进展。     

SiGe／Si应变层超晶格异质界面热稳定性的光散射研究

ＳｉＧｅ／Ｓｉ应变层超晶格异质界面热稳定性的光散射研究刘晓晗，黄大鸣，蒋最敏（复旦大学物理系和应用表面物理国家重点实验室上海２００４３３）ＲａｍａｎＳｔｕｄｙｏｎＴｈｅＩｎｔｅｒｆａｃｅＳｔａｂｉｌｉｔｙｏｆＳｕＧＥ／ＳｉＬａｙｅｒＳｕｐｅｒｌａｔｔ...     

1.55μmSi1—xGex光波导在Si1—xGex／Si多量子阱探测器集成的优…

对１。５５μｍ波长的Ｓｉ１－ｘＧｅｘ光波导和Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器的集成器件结构进行了系统的分析和优化设计。优化结果为：１）对Ｓｉ１－ｘＧｅｘ光波导，Ｇｅ含量ｘ＝０．０５，脊宽，高和腐蚀深度分别为８，３和２．６μｍ，２）对ＳＩ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器，Ｇｅ含量ｘ＝０．５，探测器由厚度为５５０ｎｍ，２３个周期的６ｎｍＳｉ０．５ＧＥ０．５＋１８ｎｍＳｉ组成，长度约２ｍｍ。     

能谷间相互作用对量子阱Ge_(0.3)Si_(0.7)/Si/Ge_(0.3)Si_(0.7)的电子能带结构的影响

采用建立在经验赝势理论基础上的推广ｋ·ｐ方法及电流密度算符技术，计算了生长在Ｇｅ０３Ｓｉ０７（００１）衬底上的量子阱Ｇｅ０３Ｓｉ０７／Ｓｉ／Ｇｅ０３Ｓｉ０７的导带电子束缚能级．详细地研究了因能谷间相互作用而引起的能级分裂情况，同时也讨论了电子束缚能级在阱平面方向上的色散关系     

New surface structure analysis of Ag-Si phase by quantitative auger electron spectroscopy method

Ag or Au was deposited on a clean Si substrate at room temperature. These systems, Ag/Si and Au/Si, were annealed at various temperatures or various heating times. Due to the annealing, Ag or Au diffused into Si and/or Si diffused into the metal. The changes of the surface composition are analyzed by a quantitative Auger Electron Spectroscopy (AES) method which is newly developed as a non-destructive method. In the case of Ag/Si, Ag migrated into the Si substrate and/or Si diffused into Ag. Then, Ag-Si solid solution was produced. After the annealing, the Ag/Si system is changed into Ag/(Ag-Si)/Si of the three-phase structure. In the case of Au/Si (Au film thickness < 15 Å), the Au film thickness became thinner by annealing. The Au/Si system always keeps the Au/Si phase after annealing, while there was no Au-Si solution area. The difference between the Ag/(Ag-Si)/Si and the Au/Si structure is attributed to the reason that Au diffuses more quickly than Ag into the Si substrate. AES results after annealing cannot be explained by the model of the formation of the three-dimensional island structure which is commonly referenced.     

稳定In/Si表面的LEED研究

利用LEED图形拟合的方法对大量不同取向In/Si表面的稳定性和小面化进行了研究，新发现了In覆盖度在1/2单层原子以下的三个稳定表面：Si(214)-In，Si(317)-In和Si(436)-In，以及In覆盖度在1单层原子左右的两个稳定表面Si(101)-In和Si(313)-In.此外还确定了In覆盖度在1单层原子左右的6个稳定In/Si表面的家族领地以及In覆盖度在1/2单层原子以下的4个稳定In/Si表面的家族领地.特别值得注意的是 Si(103)-In的家族领地相当大，甚至比最稳定的Si(1 关键词： 硅表面 铟 稳定表面 家族领地     

Influence of the Si–O–C interplayer on the flexural behaviors of C/Si–C–N composites

Carbon fiber reinforced Si–C–N matrix composite(C/Si–C–N) with a Si–O–C interlayer (C/Si–O–C/Si–C–N) was fabricated via CVI and PIP process. The flexural behaviors of C/Si–O–C/Si–C–N were investigated using the three-point-bending method and the SEM technique. The results indicated that the flexural strengh of the C/Si–O–C/Si–C–N increases with increasing temperature and the modulus of the composite is essentially unchanged. The strength of C/Si–O–C/Si–C–N is comparable to that of C/PyC/Si–C–N, and the role of Si–O–C interlayer in C/Si–C–N can rival that of the PyC interlayer. The weaker interfacial bonding and the larger thickness of Si–O–C interlayer make a contribution to this at RT while the thinner interlayer and unstable structure of Si–O–C interphase do it above 1300 °C.     

Si60团簇的结构及其与Si(111)面间碰撞的分子动力学模拟

利用紧束缚分子动力学退火方法模拟研究了Si60团簇的稳定结构和基态能量,结果表明Si60团簇为具有T对称性的截顶二十面体的富勒烯结构,平均键长为0236nm,直径为0933nm,原子结合能为4.45eVatom,JahnTeller效应对Si60团簇的结构有很大影响.通过对Si60分子和Si(111)面碰撞机理的粒子数、体积和能量不变分子动力学模拟,发现Si60分子吸附在Si(111)面所需要的垂直入射动能为40eV,Si60分子远不如C60分子稳定 关键词： 紧束缚 JahnTeller效应 碰撞     

Si(001)面上外延生长的Ru2 Si3电子结构及光学性质研究

基于第一性原理的赝势平面波方法,对异质外延关系为Ru2Si3(100)//Si(001),取向关系为Ru2Si3[010]//Si[110]正交相的Ru2Si3平衡体系下能带结构、态密度和光学性质等进行了理论计算.计算结果表明:当1.087 nm≤a≤1.099 nm时,正交相Ru2Si3的带隙值随着晶格常数a取值的增大而增大.当a取值为1.093 nm时,体系处于稳定状态,此时Ru2Si3是具有带隙值为0.773 eV的直接带隙半导体.Ru2Si3价带主要是由Si的3p,3s态电子及Ru 4d态电子构成;导带主要由Ru的4d及Si的3p态电子构成.外延稳定态及其附近各点处Ru2Si3介电函数的实部和虚部变化趋势基本一致,但外延稳定态Ru2Si3介电函数的曲线相对往低能区漂移,出现的介电峰减少且峰的强度明显增强.     

Mg-Sn-Si合金中Mg2(Si,Sn)复合相的结构与性能研究

研究了铸态Mg-Sn-Si合金中Mg₂(Si,Sn)复合相的结构、 特性以及该相对Mg-Sn-Si合金变质作用的影响. 结果表明: Sn原子能取代Mg₂Si中的部分Si生成Mg₂(Si,Sn)复合相, 该三元相与Mg₂Si, Mg₂Sn相的结构相同, 属于面心立方结构, Mg₂(Si,Sn)相的元素含量并不固定, 在Si富集区形成的Mg₂(Si,Sn)相中, Si元素含量高, 在Si贫乏区形成的Mg₂(Si,Sn)相中, Si元素含量低. Si含量较多的Mg₂(Si,Sn)相性能与Mg₂Si相接近, Sn含量较多的Mg₂(Si,Sn)相性能与Mg₂Sn相接近, 实验中发现Mg₂(Si,Sn)复合相的纳米硬度、 弹性模量与维氏硬度等物理性能介于Mg₂Si与Mg₂Sn之间, Mg₂(Si,Sn)相对汉字状Mg₂Si相的变质处理起到桥梁作用. 关键词： Mg-Sn-Si合金 2Si')" href="#">Mg₂Si 2Sn')" href="#">Mg₂Sn 2(Si,Sn)复合相')" href="#">Mg₂(Si,Sn)复合相     

In situ size measurement of Si nanoparticles and formation dynamics after laser ablation

We have developed a technique to detect Si nanoparticles selectively and to measure size in situ. Applying the technique, we have investigated formation process of Si nanoparticles after pulsed laser ablation of Si targets in Ar gas. Time-resolved photoluminescence (PL) spectroscopy revealed that PL only from Si nanoparticles is observed below 2.4 eV while PL from Si nanoparticles as well as defects in SiO₂ is observed above 2.4 eV. Therefore, Si nanoparticles can be detected selectively by excitation light with a photon energy below 2.4 eV. It is found that the onset of the PL from Si nanoparticles is delayed by approximately 0.3 ms from that of the defects and smaller Si nanoparticles. A size can be estimated by a band gap, which is roughly equal to the lowest photon energy at which Si nanoparticles can be excited. Thus, we estimated the sizes of growing Si nanoparticles. PACS 61.46.+w; 78.66.w; 07.60.Yi     

Finemet合金析出相α-Fe(Si)结构与磁性的第一性原理计算

采用基于密度泛函理论的第一性原理计算方法研究Finemet合金中析出相α-Fe(Si)的晶体结构与磁性,探讨影响立方结构α-Fe(Si)相磁性能的各个因素. 从电子自旋角度出发,分别计算分析了不同比例的Si置换α-Fe超晶格中不同位置的Fe原子后α-Fe(Si)体系的磁性能. 计算结果表明,自旋态密度是影响磁性能的关键因素. 发现Si置换α-Fe超晶格顶角处Fe原子得到的体系比取代体心位置Fe原子的体系磁性要好. 由此可以得出结论,在一定的含量范围内,随着Si含量的增加,Si出现在α-Fe超晶格中顶角位置的概率增大,α-Fe(Si)相的软磁性能提高,与实验结果相符. 本文的研究工作有助于理解Finemet合金的磁性机理. 关键词： Finemet合金 磁性能 第一性原理 态密度     

Morphology of Si nanowires fabricated by laser ablation using gold catalysts

Si nanowires (NWs) were fabricated successfully by laser ablation using Au as catalyst. Si wafers were used as the collector. The diameters of Si NWs ranged from 20 to 150 nm. Different forms of Si NWs were observed at different local sites inside a furnace: Si NWs with a high aspect ratio of length to diameter, Si NWs with defects and Si NWs with Au-containing nanoparticles being embedded. Especially, a nano-particle embedded Si NW is a new nanostructure that is observed for the first time. PACS 81.07.-b; 81.07.Bc; 81.16.-c; 81.20.-n     

Effect of high-pressure water-vapor annealing on energy transfer in dye-impregnated porous silicon

We have studied the effect of high-pressure water-vapor annealing (HWA) on the excitation energy transfer from Si nanocrystals to dye molecules in porous Si layers. Efficient photoluminescence, originating from both RhB molecules and Si nanocrystals, was observed. The behavior of the polarization memory of the photoluminescence showed the presence of energy transfer from the surface-passivated Si nanocrystals to RhB molecules. The fact that HWA, which is an effective method to stabilize and enhance the emission from Si nanocrystals in porous Si, does not suppress the energy transfer is an important result since it makes possible the realization of stable Si/dye-nanocomposite functional devices.